DE102004008600B4 - A method of deploying an occupant protection system and occupant protection system for a vehicle - Google Patents

Abstract

A method for triggering an occupant protection system for a vehicle (10), comprising at least two sensors (21, 21 ', 22, 22', 23) for triggering at least one protection means (11) in the event of an accident of the vehicle, a) a chronological sequence of collision signals (V1, V2, V3, V4) of the sensors (21, 21 ', 22, 22', 23) detected and b) used to determine an accident type, the type of accident is determined b1) based on a transit time difference (Z1, Z2) of at least two collision signals (V1, V2, V3, V4) and b2) of an impact direction, which can be determined from the spatial arrangement of the sensors (21, 21 ', 22, 22', 23) on the vehicle, whose collision signals (V1, V2 , V3, V4) were detected, and c) the determined type of accident is used to adjust the tripping behavior of the occupant protection system by d) each accident type in addition to a triggering threshold at least one further reaction parameter of an integration constant, an acceleration, a speed, and / or egg is associated with a trip, which enters into the adaptation of the tripping behavior of the occupant protection system.

Description

The invention relates to a method for triggering an occupant protection system for a motor vehicle according to claim 1 and an occupant protection system for a vehicle according to claim 5.

To improve road safety, occupant protection systems, including a control device with one or more sensors and associated restraint means, are continually being improved to ensure optimum occupant protection in the event of an accident. An improvement in the protective effect is achieved in particular by influencing the triggering thresholds and the triggering times of the occupant protection system.

Numerous occupant protection systems are already in use, which have a control unit with a centrally arranged sensor and supplemented by further sensors, the so-called assistance sensors. The assistance sensors, satellite sensors or outsourced sensors are usually mounted near the body of the vehicle. They are arranged in the vehicle depending on the specific task. For example, assistance sensors near the front of the vehicle, which are referred to as upfront sensors, are used to quickly detect a frontal collision. For example, to quickly detect a side impact, assistance sensors are mounted near the vehicle side, such as in the door area; These sensors are called side sensors.

In particular, in the event of a side impact, the time available, measured from the contact of the collision partners to the triggering of restraint means, is particularly short. This is due to the small crumple zone in the area of the vehicle side. Therefore, in the case of a side impact, it is necessary to take the triggering decision for the protection means of an occupant protection system as early as possible and to control the protection means as quickly as possible. In such a situation, a final evaluation of the acceleration signal is usually required at a time at which the accidental acceleration has not yet reached its maximum value. In order to make an early and yet reliable decision about the type of accident, ie in particular impact speed and direction, therefore, the outsourced sensors are provided. The control unit evaluates the detected acceleration values of the outsourced sensors and the acceleration values of their own centrally arranged sensors in order to be able to make a triggering decision from this.

From the DE 44 25 846 A1 A method for triggering side airbags of a safety device for motor vehicles is known in which the information of a centrally located in the vehicle acceleration sensor is linked to the information from side satellites to derive therefrom a trigger signal. Each of the sensor signals is checked to see if it exceeds predetermined thresholds; in accordance with the exceeded threshold values, the signal is classified into an acceleration class. The class assignment of the sensor signals is evaluated by means of an evaluation matrix and, depending on the result of the evaluation, optionally a trigger signal is generated. The triggering matrix determines which combination of the detected accelerations leads to a trigger signal and in which combinations no triggering of the restraint means takes place.

From the DE 101 14 277 C1 a device for detecting a side impact in a motor vehicle is known in which a triggering decision based on the signatures of the acceleration sensors for controlling the protection means is generated with a central acceleration sensor and outsourced acceleration sensors. Here, the outsourced acceleration sensors are mounted asymmetrically with respect to the vehicle longitudinal axis. Due to the asymmetrical attachment of the sensors can be closed due to geometric considerations on the impact location and the momentum transfer. In this case, both the amount and the direction of the impulse transfer can be determined.

From the DE 101 41 886 A1 a method for determining a release time for restraining means in a vehicle is known, in which the formation of two time windows for the speed reduction in a crash, the slope of the speed reduction in the respective time window and the position of the time window is determined in order in conjunction with a Impact time and the impact velocity to achieve an accurate determination of the tripping time.

However, these systems have the disadvantage that the acceleration signals of the outsourced sensors are considered or evaluated only on their own, that is, set only to a limited extent with the acceleration values of the centrally arranged sensors in relation to an accident characteristic or accident detail information for optimization of the tripping behavior of an occupant protection system.

In addition, from the DE 103 48 999 A1 as well as the DE 101 56 083 A1 or the DE 100 13 563 A1 Method for triggering an occupant protection system In occupant protection systems refer to, in which the triggering threshold is adjusted in dependence on the time sequence of the collision signals.

Object of the present invention is therefore to provide a method for triggering an occupant protection system for a vehicle and an occupant protection system, which ensure optimum occupant safety and are reliable and cost-effective.

This object is achieved by a method having the features of claim 1 and by an occupant protection system having the features of claim 5. Preferred embodiments of the invention will become apparent from the dependent claims.

An essential idea of the invention is based on the finding that the determination of the type of accident permits a statement about the severity of the accident, as a result of which a targeted adaptation of the tripping behavior of an occupant protection system can be carried out. In order to ensure optimum protection of the occupants in the event of an accident, the type of accident can be determined before and at the latest with the triggering decision and used to adjust the triggering behavior.

According to the invention, the type of accident is determined on the basis of the sequence of collision signals from sensors, that is to say the chronological occurrence of the collision signals transmitted by the affected sensors. At least two sensors are required to generate the collision signals. In particular, the temporal sequence of the collision signals of a sensor provided in a control unit of an occupant protection system and of an assistance sensor, for example an upfront or satellite sensor, is evaluated. It is also possible to evaluate the time sequence of the collision signals from two sensors arranged outside the control unit or from a sensor provided internally in the control unit and two or more assistance sensors. It is conceivable to evaluate the temporal sequence of the most diverse sensors, provided that the crash signature delivered by the sensors has a temporal resolution which is suitable for determining the type of accident. The time sequence is used to determine the type of accident, z. By reproducing a pattern or a history that can be assigned to one of several stored accident types. The collision signals of the sensors are here understood to mean their operating signals in the event of a collision. The sequence of the collision signals can be determined, in particular, on the basis of one or more threshold values which are or will be exceeded by the collision signals in the event of an accident. Exceeding the at least one threshold by a collision signal generates a time event. Based on several such time events generated by different sensors then the accident type can be determined. The at least one threshold influences in particular the sensitivity of the system and can be adjustable.

In order to adapt the tripping behavior, preferably a tripping time and / or a tripping threshold value of the at least one protective means are changed. The trip time indicates the time in the protective means of the occupant protection system, ie z. As airbag, belt tensioner or rollover protection device, are triggered.

The type of accident is determined in particular based on a transit time difference of at least two collision signals. In order to be able to make a reliable classification of the severity of the accident, it has been shown that the transit time of a deceleration signal, measured between two locally spaced measuring points, can be used as a criterion for accident characterization. On this basis, the tripping behavior can be influenced in such a way that the protection means can be used as efficiently as possible.

Preferably, the accident includes a high-speed crash, a medium-speed crash and / or a low-speed crash. Of course, this classification can be further refined to achieve an even more accurate adaptation of the tripping behavior.

In determining the type of accident can also be determined in addition an impact direction, which can be determined from the spatial arrangement of the sensors on the vehicle, the collision signals have been detected. In particular, an accident severity can be determined via the impact direction, so that the protection means can be used as efficiently as possible.

In this case, the type of accident preferably includes a frontal crash, a side crash, a rear crash, an oblique crash and / or a rollover crash.

Furthermore, each type of accident will be assigned at least one reaction parameter, which is included in the adaptation of the tripping behavior of the occupant protection system. By specifying various reaction parameters, it is possible to respond specifically to each detected type of accident.

The reaction parameters include a triggering threshold, an integration constant, an acceleration, a speed, and / or a feedback.

The values of the reaction parameters are here dimensioned in particular for optimum protection of the occupants. It can depend on the value of a parameter as well as the ratio of all values to each other in order to obtain an optimal protective effect.

Ideally, the distance from at least two sensors is at least about 25 cm. It has been found that such a distance or even a greater distance causes differences in the transit time of the collision signals which are sufficient for a reliable detection of the type of accident.

The sensors may include one or more outsourced assistance sensors to increase the detection reliability of an accident type.

Preferably, the sensors are arranged on or in the region of the vehicle body.

The sensors preferably include an acceleration sensor, a rotation rate sensor, a strain gauge, a pressure sensor and / or a magnetic sensor.

The invention further relates to an occupant protection system for a vehicle having a control unit, which is provided with at least one protection means, for. As an airbag, and at least two locally on the vehicle spaced sensors is connected. The collision signals of the sensors are detected by the control unit and triggered to trigger the protection means. The control unit is designed to carry out the method according to the invention. In particular, the functionality of the control unit is realized in software. The at least two locally spaced sensors on the vehicle sensors are understood to be mounted at different locations in the vehicle. For example, this may be a sensor arranged in the control unit and an assistance sensor in the side or front area of the vehicle. Conceivable, of course, other constellations, such. B. a sensor in the control unit and two assistant sensors or even only two or more assistance sensors that have a sufficiently large distance to determine transit time differences. However, at least one sensor in the control unit and at least one sensor outside the control unit are preferred for the invention, since meaningful chronological sequences for determining the type of accident are achieved.

Further advantages and possible applications of the present invention will become apparent from the following description in conjunction with the embodiments illustrated in the drawings.

In the description, in the claims, in the abstract and in the drawings, the terms and associated reference numerals used in the list of reference numerals recited below are used.

The drawings show in:

1 an embodiment of an arrangement of an occupant protection system for a motor vehicle with control unit and sensors;

2 a time course of several collision signals of different sensors in the event of an accident depending on the impact speed;

3 a block diagram of an embodiment of an evaluation unit for processing a sensor signal, and

4 an embodiment of a matrix of accident types, reaction parameters and their associated values according to the invention.

1 shows an arrangement of an occupant protection system for a motor vehicle 10 with control unit 20 and sensors 21 . 21 ' . 22 . 22 ' . 23 , The control unit 20 is central in the vehicle 10 , preferably arranged on the tunnel. With this controller 20 are not shown retaining means such as belt tensioners, airbag and rollover protection devices connected, which are activated in the event of a crash or other critical driving situation for the most efficient protection of the occupants.

In the laterally arranged on the vehicle assistance sensors 21 . 21 ' These are so-called side sensors, which are mainly needed for the detection of a side crash or an accident situation in which the force mainly takes place laterally. Thus, a corresponding type of accident can be detected at an early stage in order to activate the necessary protection means.

At the front of the vehicle 10 arranged assistance sensors 22 . 22 ' These are so-called upfront sensors, which are mainly needed to detect a frontal crash or an accident situation in which the force mainly occurs from the front. Thus, a corresponding type of accident can be detected at an early stage in order to activate the necessary protection means. Depending on the type of vehicle, it may be necessary to have two upfront sensors for reliable recording of the type of accident 22 . 22 ' , are arranged eccentrically to the vehicle longitudinal axis, are provided, or that as a result of the vehicle structure already a single upfront sensor 23 , preferably centered to the vehicle longitudinal axis, to secure detection of the collision situation is sufficient to be able to generate the required collision signals.

For the sake of completeness, it should be noted that the measurement principles of the assistance sensors can be acceleration sensors, pressure sensors, strain gauges, magnetoresistive sensors, etc., as well as yaw rate sensors (yaw rate sensors) that generate different collision signals depending on installation.

2 shows a time course of several collision signals depending on the impact velocity and sensor arrangement. The illustrated typical signal curves are attributable to the following accident types by impact velocity and impact direction. The waveform V1 corresponds to a typical collision signal of an upfront sensor in a high-speed crash. The waveform V2 corresponds to a typical collision signal of a central sensor at the tunnel in a high-speed crash. The waveform V3 corresponds to a typical collision signal of an upfront sensor in a low-speed crash. The waveform V4 corresponds to a typical collision signal of a center sensor in a low-speed crash. Analogously, a characterization of the rollover crash types is possible, which are not graphed here in detail.

Considering the resulting from a low-speed crash working signals V3 (upfront sensor) and V4 (tunnel sensor), it can be seen that the two collision signals for exceeding a threshold S1 are relatively far in time, which is a long signal delay at a low -Speed crash corresponds. Thus, conversely, with a relative temporal relative distance of the times to each other, in which the collision signals exceed the threshold S1, be closed to a type of accident with low-speed characteristics.

If, on the other hand, one considers the collision signals V1 (upfront sensor) and V2 (tunnel sensor) resulting from a high-speed crash, it can be seen that the two collision signals are relatively short in time to exceed a threshold S1, which results in a short signal propagation time High-speed crash corresponds. Thus, conversely, when the time points are relatively short relative to one another, at which the collision signals exceed the threshold S1, an accident type with high-speed properties can again be inferred.

Due to the diagnosed type of accident, for example, with the aid of a stored in the system matrix, as in 4 shown, a tripping threshold used as a triggering criterion are derived to bring the occupant protection device as efficiently as possible to use.

In an analogous manner, it behaves in a rollover process, which is not shown in detail graphically. The sensors detecting a rollover process emit a corresponding collision signal on rotational movements or rotational acceleration movements, from which, with the aid of a matrix stored in the system, similar to those in FIG 4 represented matrix can be derived as a tripping criterion used tripping threshold to bring the occupant protection device as efficiently as possible to use.

The minimum distance between the sensors to be compared with respect to their collision signals is at least approximately 25 cm to each other so that significant differences can be generated in the sense of a reliable evaluation.

3 shows a block diagram of an evaluation unit 30 for processing a sensor signal. In this case, the output signal a (t) of a sensor 21 . 21 ' . 22 . 22 ' . 23 for detecting accelerations an integrator 31 fed. The output signal of the sensor 21 . 21 ' . 22 . 22 ' . 23 can be used for feedback purposes of the integrator 31 a certain reset value (starting from zero) or an offset signal 24 as a fixed value in g or if required as a variable value according to 4 subtracted from. At the output of the integrator 31 there is a speed 25 in the form v (t) for further utilization. The speed 25 becomes a comparator 32 supplied, which includes a tripping threshold value used as a triggering criterion, by a value transmitter 33 can be variably adapted to the requirements. Before the speed 25 This may be for return purposes, in the case of another, not shown here integration or for adjustment purposes to the diagnosed accident type, again a certain value (starting from zero) or an offset signal 26 as a fixed value in m / s or if required as a variable value according to 4 be subtracted. Another possibility of influencing the tripping behavior is that instead of the triggering threshold in the comparator 32 or the reset values 24 . 26 an integration constant K of the integrator 31 by another value transmitter 34 is controlled to perform an adjustment to the diagnosed accident.

At the output of the comparator 32 If an activation threshold value is used as a triggering criterion, an enable signal for the protection means is generated, optionally with further enable signals 27 can be linked.

4 shows a matrix of accident types, reaction parameters and their associated values. Due to the according to 2 determined signal propagation time, can be obtained on the basis of the matrix stored in the system conclusions about the type of accident in order to gain from the corresponding values of the reaction parameters, which enter into the determination of the triggering time for the most efficient use of the protection means.

In a high-speed crash, it is advantageous if the tripping threshold used as a triggering criterion is lower than in comparison to a low-speed crash. Instead of the triggering threshold can also, as in the 3 discussed, the integration constant will be adapted to the type of accident. In this case, it is advantageous that a higher integration constant is used in a high-speed crash than in comparison to a low-speed crash. It is equally advantageous if the reset values 24 . 26 be adapted to the diagnosed type of accident according to the matrix.

For the sake of completeness, it should be noted that the collision signals to be compared need not necessarily be a sensor signal of a central sensor, but they may well be two or more collision signals from outsourced sensors with the same or different action principle.

LIST OF REFERENCE NUMBERS

10

motor vehicle

11

preservative

20

control unit

21, 21 '

side sensor

22, 22 '

front sensor

23

Central front sensor

24, 26

Reset value

25

speed

27

enable signal

30

evaluation

31

integrator

32

comparator

33, 34

valuator

at)

Output signal of a sensor

G

acceleration

v (t)

speed information

V1, V2, V3, V4

waveform

Z1, Z2

Time difference

Claims (5)

Method for triggering an occupant protection system for a vehicle ( 10 ), with at least two sensors ( 21 . 21 ' . 22 . 22 ' . 23 ) for triggering at least one protective agent ( 11 ) in an accident of the vehicle, a) a time sequence of collision signals (V1, V2, V3, V4) of the sensors ( 21 . 21 ' . 22 . 22 ' . 23 b) based on a transit time difference (Z1, Z2) of at least two collision signals (V1, V2, V3, V4) and b2) an impact direction, which results from the spatial Arrangement of the sensors ( 21 . 21 ' . 22 . 22 ' . 23 ) can be determined on the vehicle whose collision signals (V1, V2, V3, V4) were detected, and c) the determined type of accident is used to adjust the tripping behavior of the occupant protection system by d) each accident type in addition to a triggering threshold at least one further reaction parameter from an integration constant , is assigned to an acceleration, a speed, and / or a position feedback, which enters into the adaptation of the tripping behavior of the occupant protection system. A method according to claim 1, characterized in that for adapting the tripping behavior, a tripping time and / or a tripping threshold of the at least one protection means ( 11 ) is changed. A method according to claim 1 or 2, characterized in that the accident includes a high-speed crash, a medium-speed crash and / or a low-speed crash. A method according to claim 3, characterized in that the accident includes a frontal crash, a side crash, a rear crash, an oblique crash and / or a rollover crash. Occupant protection system for a vehicle, with a control unit ( 20 ) containing at least one protective agent ( 11 ) and at least two locally spaced sensors ( 21 . 21 ' . 22 . 22 ' . 23 ) whose collision signals (V1, V2, V3, V4) from the control unit ( 20 ) and to trigger the protective device ( 11 ), characterized in that the control unit ( 20 ) is designed for carrying out the method according to one of the preceding claims.

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